img_mpeg2_vld_inter.h64

dm642函数库

;* ======================================================================== *;
;*  TEXAS INSTRUMENTS, INC.                                                 *;
;*                                                                          *;
;*  IMGLIB  DSP Image/Video Processing Library                              *;
;*                                                                          *;
;*      Release:        Revision 1.04b                                      *;
;*      CVS Revision:   1.11    Sun Sep 29 03:32:26 2002 (UTC)              *;
;*      Snapshot date:  23-Oct-2003                                         *;
;*                                                                          *;
;*  This library contains proprietary intellectual property of Texas        *;
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;*  This software is licensed for use with Texas Instruments TMS320         *;
;*  family DSPs.  This license was provided to you prior to installing      *;
;*  the software.  You may review this license by consulting the file       *;
;*  TI_license.PDF which accompanies the files in this library.             *;
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;*          Copyright (C) 2003 Texas Instruments, Incorporated.             *;
;*                          All Rights Reserved.                            *;
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;*  Assembler compatibility shim for assembling 4.30 and later code on      *;
;*  tools prior to 4.30.                                                    *;
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;*  End of assembler compatibility shim.                                    *;
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* ========================================================================= *
*   TEXAS INSTRUMENTS, INC.                                                 *
*                                                                           *
*   NAME                                                                    *
*       IMG_mpeg2_vld_inter                                                 *
*                                                                           *
*   PLATFORM                                                                *
*       C6400                                                               *
*                                                                           *
*   REVISION DATE                                                           *
*       23-May-2002                                                         *
*                                                                           *
*   DESCRIPTION                                                             *
*       This routine takes a bitstream of an MPEG-2 non-intra coded         *
*       macroblock and returns the decoded IDCT coefficients. The routine   *
*       is implemented as specified in the MPEG-2 standard text (ISO/IEC    *
*       13818-2). The routine checks the coded block pattern (cbp),         *
*       performs coefficient decoding inlcuding, variable length decode,    *
*       run-length expansion, inverse zigzag, dequantization, saturation    *
*       and mismatch control.                                               *
*                                                                           *
*   USAGE                                                                   *
*       This routine is C callable, and has the following C prototype:      *
*                                                                           *
*       void IMG_mpeg2_vld_inter                                            *
*       (                                                                   *
*           const short    *restrict Wptr,                                  *
*           short          *restrict outi,                                  *
*           IMG_mpeg2_vld  *restrict Mpeg2v,                                *
*           int            mode_12Q4,                                       *
*           int            num_blocks,                                      *
*           int            bsbuf_words                                      *
*       );                                                                  *
*                                                                           *
*         Wptr:   Pointer to array that contains quantization matrix. The   *
*                 elements of the quantization matrix in *Wptr must be      *
*                 ordered according to the scan pattern used (zigzag or     *
*                 alternate scan). Video format 4:2:0 requires one          *
*                 quantization matrix (64 array elements).  For formats     *
*                 4:2:2 and 4:4:4 two quantization matrices (one for luma   *
*                 and one for chroma) must specified in the array (128      *
*                 array elements).                                          *
*                                                                           *
*         outi:   Pointer to the IDCT coefficients output array             *
*                 (6*64 elements), elements must be set to zero prior to    *
*                 function call.                                            *
*                                                                           *
*         Mpeg2v: Pointer to the context object containing the coding       *
*                 parameters of the MB to be decoded and the current state  *
*                 of the bitstream buffer. The structure is described       *
*                 below.                                                    *
*                                                                           *
*      mode_12Q4: 0: Coefficients are returned in normal 16-bit integer     *
*                 format.                                                   *
*                 Otherwise: Coefficients are returned in 12Q4 format       *
*                 (normal 16-bit integer format left shifted by 4). This    *
*                 mode is useful for directly passing the coefficients      *
*                 into the IMG_idct_8x8 routine.                            *
*                                                                           *
*     num_blocks: Number of blocks that the MB contains. Valid values are   *
*                 6 for 4:2:0, 8 for 4:2:2 and 12 for 4:4:4 format.         *
*                                                                           *
*    bsbuf_words: Size of bitstream buffer in words. Must be a power of 2.  *
*                 Bitstream buffer must be aligned at an address boundary   *
*                 equal to its size in bytes (bitstream buffer is           *
*                 addressed circularly by this routine.)                    *
*                                                                           *
*       The structure Mpeg2v is defined as follows:                         *
*                                                                           *
*           #ifndef IMG_MPEG2_VLD_STRUCT_                                   *
*           #define IMG_MPEG2_VLD_STRUCT_ 1                                 *
*                                                                           *
*           typedef struct {                                                *
*             unsigned int  *bsbuf;      // pointer to bitstream buffer     *
*             unsigned int  next_wptr;   // next word to read from buffer   *
*             unsigned int  bptr;        // bit position within word        *
*             unsigned int  word1;       // word aligned buffer             *
*             unsigned int  word2;       // word aligned buffer             *
*             unsigned int  top0;        // top 32 bits of bitstream        *
*             unsigned int  top1;        // next 32 bits of bitstream       *
*             const unsigned char *scan; // inverse zigzag scan matrix      *
*             unsigned int  intravlc;    // intra_vlc_format                *
*             unsigned int  quant_scale; // quant_scale                     *
*             unsigned int  dc_prec;     // intra_dc_precision              *
*             unsigned int  cbp;         // coded_block_pattern             *
*             unsigned int  fault;       // fault condition (returned)      *
*             unsigned int  reserved;    // reserved                        *
*           } IMG_mpeg2_vld;                                                *
*                                                                           *
*           #endif                                                          *
*                                                                           *
*       The Mpeg2v variables should  have a fixed layout since they are     *